Finding the Fourth Proportional to 21,559.50, 29,752.20 and 12,128.22

Step by Step Solution

1. Step 1: Write the proportion equation
   21,559.50 : 29,752.20 = 12,128.22 : x
2. Step 2: Convert to fraction form
   21,559.50/29,752.20 = 12,128.22/x
3. Step 3: Cross multiply
   21,559.50x = 29,752.20 × 12,128.22
4. Step 4: Simplify right side
   21,559.50x = 360,841,227.08
5. Step 5: Solve for x
   x = 360,841,227.08/21,559.50
6. Step 6: Final answer
   x = 16,736.99